/*
 * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
 *
 * The MIT License
 * Copyright © 2014-2022 Ilkka Seppälä
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package com.iluwatar.event.aggregator;

import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

/** EventEmitter is the base class for event producers that can be observed. */
public abstract class EventEmitter {

  private final Map<Event, List<EventObserver>> observerLists;

  public EventEmitter() {
    observerLists = new HashMap<>();
  }

  public EventEmitter(EventObserver obs, Event e) {
    this();
    registerObserver(obs, e);
  }

  /**
   * Registers observer for specific event in the related list.
   *
   * @param obs the observer that observers this emitter
   * @param e the specific event for that observation occurs
   */
  public final void registerObserver(EventObserver obs, Event e) {
    if (!observerLists.containsKey(e)) {
      observerLists.put(e, new LinkedList<>());
    }
    if (!observerLists.get(e).contains(obs)) {
      observerLists.get(e).add(obs);
    }
  }

  protected void notifyObservers(Event e) {
    if (observerLists.containsKey(e)) {
      observerLists.get(e).forEach(observer -> observer.onEvent(e));
    }
  }

  public abstract void timePasses(Weekday day);
}
